Madias J E, Khan M, Manyam B
Cardiology Division, Mount Sinai/Elmhurst Hospital Center, NY 11373, USA.
Clin Cardiol. 1997 May;20(5):489-92. doi: 10.1002/clc.4960200517.
Exercise electrocardiogram (ECG) has a high rate of false negative results in comparison with simultaneously performed thallium-201 perfusion scintigraphy, particularly in patients with single-vessel coronary artery disease, low exercise workload, inadequate heart rate rise, and resting ECG abnormalities. We present the case of a patient in whom thallium-201 SPECT scintigram revealed equally extensive and severe myocardial ischemia in two myocardial planes opposite each other. The accompanying exercise ECG did not disclose ischemic changes despite the adequacy of heart rate rise in this patient with severe right and left anterior descending coronary artery disease. We propose, as an explanation for this phenomenon, that in this patient the ischemic ST-segment vectors of equal magnitude and direction but of opposite sense, generated during stress, cancelled each other ("ischemic ST-segment counterpoise"), thus rendering the exercise ECG normal.
与同时进行的铊-201灌注闪烁扫描相比，运动心电图（ECG）的假阴性结果发生率较高，尤其是在单支冠状动脉疾病、运动负荷低、心率上升不足以及静息心电图异常的患者中。我们报告了一例患者，其铊-201单光子发射计算机断层扫描（SPECT）闪烁图显示在两个相对的心肌平面上存在同样广泛且严重的心肌缺血。尽管该患有严重右冠状动脉和左前降支冠状动脉疾病的患者心率上升充分，但随附的运动心电图并未显示缺血改变。我们提出，作为对这一现象的解释，在该患者中，应激期间产生的大小相等、方向相同但意义相反的缺血性ST段向量相互抵消（“缺血性ST段平衡”），从而使运动心电图正常。
